Internet Protocol Version 6 (IPv6) Overview

In this article

An overview of the Internet Protocol version 6 (IPv6) technology in Windows Server® 2012, its practical applications, new and changed functionality, and links to additional resources.

Technology description

IPv6 is the replacement for IP version 4 (IPv4), the Internet layer protocol of the TCP/IP protocol stack in prevalent use around the world today. IPv6 solves many of the problems and shortcomings of IPv4, providing an Internet layer protocol that can scale to the future needs of devices that will connect to the Internet. The most prominent feature of IPv6 is the use of 128-bit addresses (rather than 32-bit addresses), which allows for 3.4 × 1038 possible addresses, more than enough to handle today's needs and those of the foreseeable future.

IPv6 is not backward compatible with IPv4. An IPv6-only node cannot communicate with an IPv4-only node. Therefore, a careful transition must occur from an IPv4-only network to a network that supports both IPv4 and native IPv6. As more nodes and applications on the network become IPv6-enabled, the majority of traffic on your network shifts over time from mostly IPv4 to mostly IPv6. This is the current goal of an IPv6 transition strategy. Due to the prevalence of nodes, devices, applications, and network management systems that support only IPv4 now, with few exceptions, the goal of your IPv6 transition strategy is to migrate from an IPv4-only network to a network that supports both IPv4 and IPv6 traffic, not to migrate to an IPv6-only network.

Practical applications

Today's practical applications of IPv6 include the following:

An addressing scheme that scales to the largest of networks

Current public IPv4 address space is limited and usually reserved for Internet-facing hosts. Even when you use the IPv4 private address space on your intranet, IPv4-only intranets can only scale so far. With IPv6, public address space is very easy to obtain and private address space, using Unique Local Address (ULA) prefixes, can apply to each site of your organization. The combination of public address space and ULA prefixes allow you to scale your intranet to an enormous size.

Ability to use IPv6-only services and applications

The latest versions of Windows have features that are either IPv6-only or work best in an IPv6-capable environment. For example, DirectAccess works most efficiently when your intranet has a native IPv6 infrastructure.

Ability to connect with IPv6-only nodes outside your intranet

In some areas of the world that have limited IPv4 address space, organizations are connecting to the Internet with IPv6 and performing protocol translations to communicate with IPv4-only resources. Having a native IPv6 infrastructure allows you to connect and communicate with these organizations most efficiently.

Ability to connect to your network from an IPv6-only Internet access point

In some areas of the world, Internet access uses only IPv6. Having IPv6-capable hosts, a native IPv6 intranet infrastructure, and a presence on the IPv6 Internet makes communication with your intranet from these locations much more efficient.

New functionality

The new features of IPv6 in Windows Server 2012 and Windows® 8 address better connectivity on the Internet, a protocol translation service for DirectAccess clients, and better manageability of IPv6 settings through Windows PowerShell.

Better Internet connectivity

As Internet properties connect to both the IPv4 and IPv6 Internets, a problem can occur on a small number of hosts where there no routing path to the IPv6 Internet. This causes a delay in connectivity to the Internet resource because the host attempts a connection over IPv6, which fails, before attempting the connection over IPv4. IPv6 in Windows Server 2012 and Windows 8 detects this condition and prevents the initial connection attempt over IPv6.

What value does this change add?

More efficient connectivity to Internet properties for those hosts that have a global IPv6 address and a default route on the Internet, but no routing path.

What works differently?

IPv6 attempts to connect to a well-known resource on the IPv6 Internet. If this connection fails, Windows marks the network interfaces that have this condition as unusable for IPv6, causing the IPv6 destination addresses for the Internet properties to be unreachable. Therefore, Windows Server 2012 and Windows 8 does not attempt a connection over IPv6.

NAT64/DNS64

A NAT64/DNS64 work together to translate incoming connection traffic from an IPv6 node to IPv4 traffic. The DNS64 resolves the name of an IPv4-only host to a translated IPv6 address. The NAT64 translates the incoming IPv6 traffic to IPv4 traffic and performs the reverse translation for response traffic.

What value does this change add?

DirectAccess clients only send IPv6 traffic across the DirectAccess connection to the DirectAccess server. With NAT64/DNS64 support on a Windows Server 2012-based DirectAccess server, DirectAccess clients can now initiate communications with IPv4-only hosts on the intranet.

What works differently?

NAT64/DNS64 is new feature of DirectAccess in Windows Server 2012.

Windows PowerShell

To support better manageability across Windows, Windows Server 2012 includes a new set of Windows PowerShell cmdlets to perform command-line and script-based configuration of IPv6 settings. Although Netsh.exe commands for IPv6 configuration are still supported, Windows PowerShell is recommended.

What value does this change add?

The ability to manage IPv6 settings in the common management environment of Windows PowerShell, including scripts and workflows.

What works differently?

In previous versions of Windows, command-line management of IPv6 settings was done with the Netsh.exe command.

See also

See the following table for links to additional resources about IPv6 in Windows Server 2012.